1. Field of the Invention
The present invention relates to a heater unit for use in a self-heating container. In particular it relates to parts for a solid fuel heater unit with a manually operable igniter for automatically igniting the solid fuel. The unit is particularly suitable for use in disposable self-heating food containers, but is not limited to this.
2. Description of the Related Art
A food container with a built-in heater of this type is described in published International patent application WO-A-83/00425.
The heater includes a top heat spreading layer, and a layer of exothermic material having internal walls and arranged on a heat insulating non-combustible layer. Under the non-combustible layer, a slidable striker is positioned in contact with a friction responsive element. A primer material is supported in the non-combustible layer between the friction responsive element and the exothermic material for initiating the exothermic reaction once the primer has been ignited.
Such an arrangement is quite complicated and involves a large number of different parts. In at least some of the embodiments described in WO-A-83/00425, the parts are "stacked" loosely together in the base of the food container, and the design relies on at least a portion of the container itself to hold the heater parts together in the correct position.